The present invention relates to a bladderless pipeliner and method for using same. Prior apparatus and methods for repairing pipelines have included an inversion bladder tube as well as a felt liner tube. The liner tube is positioned inside the bladder tube and the action of the bladder tube during inversion causes the liner and the bladder tube to invert together. Once the inversion is complete the bladder that was originally on the outside of the liner is reversed to be on the inside, and the liner which was originally inside the bladder has been reversed to be outside the bladder. The bladder is then inflated to press the liner against the sewer pipe wall. These two together may be referred to as a liner/bladder assembly.
In these prior art liner/bladder assemblies, the bladder is longer than the liner. The end of the bladder includes a wick and a source of vacuum for facilitating the introduction of resin into the bladder tube to cause impregnation of the liner tube. Since the bladder is longer than the liner, the bladder continues to invert a short distance even when the liner is fully inverted. The bladder portion that extends past the end of the liner keeps the end of the liner open so there is no need to cut the end of the liner.
The bladder material used in the prior art has sometimes been made of reinforced urethane. Urethane withstands heat generated during curing of the resin. Urethane also has an excellent stretch characteristic and that is important for the bladder to be sized somewhat smaller than the host pipe. The bladder and liner then both stretch under pressure leaving a smooth bore interior of the newly cured-in-place liner.
The urethane bladder is very expensive. It represents approximately 60% of the liner/bladder assembly in raw material cost. Bladder material must be slit into the appropriate lay flat size. It is then welded into a tube and air tested for leaks and burst pressure. Then the liner tube is pulled inside of the bladder tube and this can be a difficult task, especially if the lengths are long. The bladder tube must be laid out straight with a rope passing through it so that the liner can be pulled through the bladder. If the liner is 200 feet long the manufacturing facility must have an assembly table that is at least 200 feet long also.
Therefore, a primary object of the present invention is the provision of an improved bladderless pipeliner and method for using same.
A further object of the present invention is the use of a bladderless pipeliner which does not include an inversion bladder.
A further object of the present invention is the provision of an apparatus and method which are economical to use, efficient in operation, and durable after installing.